English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Dynamically, cosmic rays with energies above about one GeV/nucleon may beimportant agents of galaxy evolution. Their pressures compare with the thermaland magnetic ones impacting galactic gas accretion, fountains and galacticoutflows, and alter the mass cycling between the gas phases, its efficiencydepends on the properties of CR transport in the different media. We aim tostudy the dynamical role of CRs in shaping the interstellar medium of a galaxywhen changing their propagation mode. We perform MHD simulations with the AMRcode RAMSES of the evolution of the same isolated galaxy (dwarf galaxy of$10^{11}$ M$_{\odot}$ down to 9-pc resolution) and compare the impact of thesimplest cosmic-ray transport assumption of uniform diffusion. We have alsoupdated the observational relation seen between the $\gamma$-ray luminositiesand SFR of galaxies using the latest detection of Fermi LAT sources. We findthat the radial and vertical distributions, and mass fractions of the gas inthe different phases are marginally altered when changing CR transport. Weobserve positive feedback of CR on the amplification of the magnetic field inthe inner half of the galaxy, except for fast isotropic diffusion. The increasein CR pressure for slow or anisotropic diffusion can suppress star formation byup to 50\%, but the dual effect of cosmic-ray pressure and magneticamplification can reduce star formation by a factor 2.5. The $\gamma$-rayluminosities and SFR of the simulated galaxies are fully consistent with thetrend seen in the observations in the case of anisotropic $10^{27.5-29}$ cm$^2$s$^{-1}$ diffusion and for isotropic diffusion slower or equal to $3 \times10^{28}$cm$^2$ s$^{-1}$. These results, therefore, do not confirm claims ofvery fast $10^{29-31}$ cm$^2$ s$^{-1}$ diffusion to match the Fermi LATobservations.

Cosmic-ray diffusion and the multi-phase interstellar medium in a dwarf galaxy. I. Large-scale properties and $\gamma$-ray luminosities